Abstract
Single-file focusing and minimum interdistance of micron-size objects in a sample is a prerequisite for accurate flow cytometry measurements. Here, we report analytical models for predicting the focused width of a sample stream b as a function of channel aspect ratio α, sheath-to-sample flow rate ratio f and viscosity ratio λ in both 2D and 3D focusing. We present another analytical model to predict spacing between an adjacent pair of objects in a focused sample stream as a function of sample concentration C, mobility ϕ of the objects in the prefocused and postfocused regions and flow rate ratio f in both 2D and 3D flow focusing. Numerical simulations are performed using Ansys Fluent VOF model to predict the width of sample stream in 2D and 3D hydrodynamic focusing for different sample-to-sheath viscosity ratios, aspect ratios and flow rate ratios. Experiments are performed on both planar and three-dimensional devices fabricated in PDMS to demonstrate focusing of sample stream and spacing of polystyrene beads in the unfocused and focused stream at different sample concentrations C. The predictions of the analytical model and simulations are compared with experimental data, and a good match is found (within 12 %). Further, mobility of objects is experimentally studied in 2D and 3D focusing, and the spread of the mobility data is used as tool for the demonstration of particle focusing in flow cytometer applications.
Similar content being viewed by others
References
Amini H, Lee W, Di Carlo D (2014) Inertial microfluidic physics. Lab Chip 14:2739–2761. doi:10.1039/c4lc00128a
Chang CC, Huang ZX, Yang RJ (2007) Three-dimensional hydrodynamic focusing in two-layer polydimethylsiloxane (PDMS) microchannels. J Micromech Microeng 17(8):1479–1486
Chen Y, Nawaz AA, Zhao Y et al (2014) Standing surface acoustic wave (SSAW)-based microfluidic cytometer. Lab Chip 14:916–923. doi:10.1039/c3lc51139a
Daniele MA, Boyd DA, Mott DR, Ligler FS (2014) 3D hydrodynamic focusing microfluidics for emerging sensing technologies. Biosens Bioelectron 67:25–34. doi:10.1016/j.bios.2014.07.002
Di Carlo D (2009) Inertial microfluidics. Lab Chip 9:3038–3046. doi:10.1039/b912547g
Frankowski M, Simon P, Bock N et al (2015) Simultaneous optical and impedance analysis of single cells: a comparison of two microfluidic sensors with sheath flow focusing. Eng Life Sci 15:286–296. doi:10.1002/elsc.201400078
Golden JP, Justin GA, Nasir M, Ligler FS (2012) Hydrodynamic focusing-a versatile tool. Anal Bioanal Chem 402:325–335. doi:10.1007/s00216-011-5415-3
Holmes D, Morgan H, Green NG (2006) High throughput particle analysis: combining dielectrophoretic particle focussing with confocal optical detection. Biosens Bioelectron 21:1621–1630. doi:10.1016/j.bios.2005.10.017
Jung H, Chun M-S, Chang M-S (2015) Sorting of human mesenchymal stem cells by applying optimally designed microfluidic chip filtration. Analyst 140:1265–1274. doi:10.1039/c4an01430h
Justin GA, Denisin AK, Nasir M et al (2012) Hydrodynamic focusing for impedance-based detection of specifically bound microparticles and cells: implications of fluid dynamics on tunable sensitivity. Sensors Actuators, B Chem 166–167:386–393. doi:10.1016/j.snb.2012.02.077
Kim JS, Ligler FS (2010) The Microflow Cytometer. PAN Stanford Publishing, Singapore. ISBN 9789814267410
Kim DS, Kim DS, Han K, Yang W (2009) An efficient 3-dimensional hydrodynamic focusing microfluidic device by means of locally increased aspect ratio. Microelectron Eng 86:1343–1346. doi:10.1016/j.mee.2009.01.017
Knight J, Vishwanath A, Brody J, Austin R (1998) Hydrodynamic focusing on a silicon chip: mixing nanoliters in microseconds. Phys Rev Lett 80:3863–3866. doi:10.1103/PhysRevLett.80.3863
Lee G-B, Chang C-C, Huang S-B, Yang R-J (2006) The hydrodynamic focusing effect inside rectangular microchannels. J. Micromechanics Microengineering 16:1024–1032. doi:10.1088/0960-1317/16/5/020
Nawaz AA, Zhang X, Mao X et al (2014) Sub-micrometer-precision, three-dimensional (3D) hydrodynamic focusing via “microfluidic drifting”. Lab Chip 14:415–423. doi:10.1039/c3lc50810b
Rodriguez-Trujillo R, Mills CA, Samitier J, Gomila G (2007) Low cost micro-Coulter counter with hydrodynamic focusing. Microfluid Nanofluidics 3:171–176. doi:10.1007/s10404-006-0113-8
Sajeesh P, Doble M, Sen AK (2014) Hydrodynamic resistance and mobility of deformable objects in microfluidic channels. Biomicrofluidics 8:1–23. doi:10.1063/1.4897332
Sajeesh P, Manasi S, Doble M, Sen AK (2015) Microfluidic device with focusing and spacing control for resistance based sorting of droplets and cells. Lab Chip 15:3738–3748. doi:10.1039/C5LC00598A
Selvam B, Merk S, Govindarajan R, Meiburg E (2007) Stability of miscible core—annular flows with viscosity stratification. J Fluid Mech 592:23–49. doi:10.1017/S0022112007008269
Sen AK, Bhardwaj P (2012) Microfluidic system for rapid enumeration and detection of microparticles. J Fluids Eng 134:111401. doi:10.1115/1.4007805
Stiles T, Fallon R, Vestad T et al (2005) Hydrodynamic focusing for vacuum-pumped microfluidics. Microfluid Nanofluidics 1:280–283. doi:10.1007/s10404-005-0033-z
Stone HA, Stroock AD, Ajdari A (2004) Engineering flows in small devices. Annu Rev Fluid Mech 36:381–411. doi:10.1146/annurev.fluid.36.050802.122124
Sundararajan N, Pio MS, Lee LP, Berlin AA (2004) Three-dimensional hydrodynamic focusing in polydimethylsiloxane (PDMS) microchannels. J Microelectromechanical Syst 13:559–567. doi:10.1109/JMEMS.2004.832196
Takayama S, McDonald JC, Ostuni E, et al (1999) Patterning cells and their environments using multiple laminar fluid flows in capillary networks. In: Proceedings of the National Academy of Sciences of the United States of America. pp 5545–5548
Testa G, Persichetti G, Bernini R (2015) Micro flow cytometer with self-aligned 3D hydrodynamic focusing. Biomed Opt Express 6:54–62. doi:10.1364/BOE.6.000054
Torquato S (1995) Nearest-neighbour statistics for packings of hard spheres and disks. Phys Rev E 51:3170–3182. doi:10.1103/PhysRevE.51.3170
Tripathi S, Chakravarty P, Agrawal A (2014) On non-monotonic variation of hydrodynamically focused width in a rectangular microchannel. Curr Sci 107:1260–1274
Yan S, Zhang J, Li M et al (2014) On-chip high-throughput manipulation of particles in a dielectrophoresis-active hydrophoretic focuser. Sci Rep 4:5060. doi:10.1038/srep05060
Zeng J, Deng Y, Vedantam P et al (2013) Magnetic separation of particles and cells in ferrofluid flow through a straight microchannel using two offset magnets. J Magn Magn Mater 346:118–123. doi:10.1016/j.jmmm.2013.07.021
Zhou J, Papautsky I (2013) Fundamentals of inertial focusing in microchannels. Lab Chip 13:1121–1132. doi:10.1039/c2lc41248a
Zhuang GS, Jensen TG, Kutter JP (2008) Three-dimensional hydrodynamic focusing over a wide reynolds number range using a two-layer microfluidic design. Twelfth international conference on miniaturized systems for chemistry and life sciences 2008. San Diego, California, pp 1357–1359
Acknowledgments
The authors would like to thank DST and DBT India and IIT Madras for providing the financial support for the project. We thank Chemical Engineering Department IIT Madras, for providing an additional syringe pump which was required for the experiments. We acknowledge MEMS Lab, Department of EE, IIT Madras, for supporting with the photolithography work. The authors also acknowledge P. G. Senapathy Computer Center, IIT Madras, for providing Virgo cluster facility for the simulations. Our special thanks to Interdisciplinary Program, IIT Madras, which enabled this work.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Shivhare, P.K., Bhadra, A., Sajeesh, P. et al. Hydrodynamic focusing and interdistance control of particle-laden flow for microflow cytometry. Microfluid Nanofluid 20, 86 (2016). https://doi.org/10.1007/s10404-016-1752-z
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/s10404-016-1752-z